Ulnar volar zone

Question 1

Ulnar volar zone

Answer 1

Pisiform
Hook of Hamate
FCU
ulnar nerve compression

Question 2

ulnar nerve compression

Answer 2

Pathophysiology
• Compression of the ulnar nerve
• Compression of Guyon’s canal
• Ulnar nerve runs behind the medial epicondyle through the cubital tunnel and enters the forearm between the two heads of FCU (runs between FCU and FDP). At the wrist , the ulnar nerve passes superficial to the transverse carpal ligament
• Ulnar nerve innervates: FCU, FDP (3rd and 4th digit0, adductor pollicis, dorsal and palmar interossei, 3rd and 4th lumbricals, abductor digiti minimi, opponens digiti minimi, flexor digiti minimi.

Prevalence 
•	Cyclists
Patient history
•	MOI
o	Cyclists supporting body weight over a long duration
o	Compression of Guyon’s canal

Question 3

ulnar nerve compression Ax & Mx

Answer 3

Ax
•	Forearm
o	FCU, FDP (medial half) weakness
•	Hand
o	Muscle weakness in hypothenar muscles (AbDM, FDM, ODM), dorsal and palmar interossei, lumbricals (3rd and 4th fingers), adductor pollicis, palmaris brevis
•	Sensory
o	Pain and paraesthesia to little finger and ulnar side of 4th finger. 
o	Weakness develops later

Differential diagnosis
• Carpal tunnel syndrome

Management
•	NSAIDs
•	Splinting
•	Modification of cycling biomechanics (advice and education)
•	Neural glides

Question 4

Pisiform OA

Answer 4

Palpate pisiform: ulnar side. Sesamoid bone.

With wrist in flexion you can glide it medially and laterally

Question 5

FCU tendonopathy

Answer 5

Palpate FCU
Resist wrist flexion and UD
Pain may indicate tendon changes

Question 6

Hook of hammate

Answer 6

Palp hook of hammate
Hook portion of the hamate can break off in stick sports such as golf, hockey, baseball.
Palpate deep and firm 2cm distal + medial from the pisiform
Tenderness may indicate a fracture